The SD UHS-1 cards truly surprised me! I also learned that the SDXC readers in Retina MacBook Pro's are direct to the logic board and transfer at 2.5GT/s, which is well into the GB/s range. The old MacBook Pro's used to have their SDXC readers attached to the USB 2.0 bus, so they were limited to a theoretical maximum of 60MBps.

I'm quite happy with new SDHC cards!

So I'm guessing you got the 6D? Or are these speeds with your MacBook Pro? How did you come up with the CF card speeds? With my 32GB Transcend I've gotten >100MB/sec sustained via the Lexar CF/SD Pro USB3 reader to my mSATA SSD on my laptop (after recent Lexar firmware update). Sure that's reads, but writes are supposed to be a good bit higher. Or was your OP about whether the SDXC/UHS-1 cards would be significantly slower than modern CF cards?

The SD UHS-1 cards truly surprised me! I also learned that the SDXC readers in Retina MacBook Pro's are direct to the logic board and transfer at 2.5GT/s, which is well into the GB/s range. The old MacBook Pro's used to have their SDXC readers attached to the USB 2.0 bus, so they were limited to a theoretical maximum of 60MBps.

I'm quite happy with new SDHC cards!

So I'm guessing you got the 6D? Or are these speeds with your MacBook Pro? How did you come up with the CF card speeds? With my 32GB Transcend I've gotten >100MB/sec sustained via the Lexar CF/SD Pro USB3 reader to my mSATA SSD on my laptop (after recent Lexar firmware update). Sure that's reads, but writes are supposed to be a good bit higher. Or was your OP about whether the SDXC/UHS-1 cards would be significantly slower than modern CF cards?

The test was with my MacBook Pro, I did get a 6D too.

I used a Delkin USB 3.0 reader for the CF cards. And I reran the SD test with the Delkin and got numbers that were statistically identical.

I used BlackMagic's Disk Speed Test app for Mac to test speeds.

I had assumed that the UHS-1's wouldn't compete with the modern CF cards.

The SD UHS-1 cards truly surprised me! I also learned that the SDXC readers in Retina MacBook Pro's are direct to the logic board and transfer at 2.5GT/s, which is well into the GB/s range. The old MacBook Pro's used to have their SDXC readers attached to the USB 2.0 bus, so they were limited to a theoretical maximum of 60MBps.

I'm quite happy with new SDHC cards!

Was the test done in a Mac or a camera? There is no way a SD card will operate that fast in a 5D MK III, maybe a 6D. Test methods can make a huge difference in file transfer speed. The fastest speed is usually by transfering very large files, 1GB for example. The file format of the card can allow higher speeds as well, because compression rates vary.Transfering a large number of jpeg files will be slower.

C'mon. Stop supporting CF tech. SD is catching up in a more reliable and convenient package and on top of that its less expensive. At the current speeds they both are way passed practical speeds from what current cameras offer. Let CF die...

C'mon. Stop supporting CF tech. SD is catching up in a more reliable and convenient package and on top of that its less expensive. At the current speeds they both are way passed practical speeds from what current cameras offer. Let CF die...

My d30 is CF only and I need to support CF until another format like XQD is adopted on canon. SD really sucks on the mk3.

C'mon. Stop supporting CF tech. SD is catching up in a more reliable and convenient package and on top of that its less expensive. At the current speeds they both are way passed practical speeds from what current cameras offer. Let CF die...

My d30 is CF only and I need to support CF until another format like XQD is adopted on canon. SD really sucks on the mk3.

Haha I see I just want camera manufacturers to stop CF slots. It'll save them space for other electronics and it'll make our end a lot easier when all cameras have the same standard and computers can easily take SD.

C'mon. Stop supporting CF tech. SD is catching up in a more reliable and convenient package and on top of that its less expensive. At the current speeds they both are way passed practical speeds from what current cameras offer. Let CF die...

My d30 is CF only and I need to support CF until another format like XQD is adopted on canon. SD really sucks on the mk3.

Haha I see I just want camera manufacturers to stop CF slots. It'll save them space for other electronics and it'll make our end a lot easier when all cameras have the same standard and computers can easily take SD.

Actually, I only see the SD physical interface as being more reliable than CF. I personally think the CF cards themselves (at least electronics inside) tend to be built in such a way as to be more reliable. An SD card has significantly smaller amount of space for NAND dies and controller, while the CF card has more room for more dies and potentially better controller which can do a better job of cleaning up space that's not being used to keep write speeds high.

Now, I very much can't wait to see XQD being widely adopted. Must faster theoretical throughput via PCIe, plus I think with a simple adapter I can stick it into my laptop's ExpressCard slot and read it at extremely high rates. Plus slightly smaller size than CF.